Slip ring cutting machine



March 23, 1948. T, SCHULER SLIP RING cu rwme MACHINE Filed June 30, 1945 N @N Wm MN MW mww r W m L QM v\ Patented Mar. 23, 1948 C'UNITE STATES PATENT FFICE SLIP RING CUTTING MACHINE Leo T. Schuler, Ruthven, Iowa Application June 30, 1945, Serial No. 602,623

5 Claims. (01. 82-4) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without payment to me of any royalty thereon.

This invention relates to a portable turning tool and is particularly adapted to the truing up and refinishing of the slip rings which are mounted on the rear of the hub of an electrically controlled variable pitch aircraft propeller of which the Curtiss electric propeller is an example.

An engine lathe of large enough capacity to swing the larger size propellers without disassembly of the blades from the hubs would be prohibitive both as to size and cost, and therefore, prior to this invention, it has been the custom when the slip rings became scarred or pitted to such an extent as would seriously affect the brush contact, to remove the propeller from the aircraft, disassemble the blades from the hub. swing the hub in a lathe of suitable capacity, and refinish the outer surface of the rings by turning. But even where the blades are disassembled from the hub, a lathe of considerable size and weight is required.

Such a lathe cannot readily be made a part of a mobile repair unit, but, because of the large size and weight, is furnished only to general depots. It had therefore become the custom when the slip rings of a propeller were worn or damaged, to remove the propeller from the shaft and ship it to a general depot for refinishing, where the blades are disassembled from the hub, the slip rings turned, the hub and blades reassembled, and the repaired propeller shipped back to the repair unit from which it was sent, with the consequent loss of the time that the propeller was in transit.

It therefore became an object of this invention to provide a portable turning tool, light enough to be easily handled by a single repairman, but equally as effective in performing the intended function as an engine lathe weighing several tons, to the end that each and every mobile repair unit may be possessed of one of the improved turning tools at a relatively small total cost.

Another object is to provide simple and inexpensive means whereby the several sizes of propellers in current use may be operated upon with a single turning tool.

I attain these and other objects and advantages in the mechanism hereinafter described and shown in the drawing, wherein:

Fig. 1 is an end elevation of the assembled tool,

a portion being broken away to show the interior construction.

Fig. 2 is an axial section taken at 22 of Fig. 1.

Like reference characters refer to like parts throughout the several views.

Referring now to the drawing, an arbor l0 is of such external dimensions as will fit snugly into the propeller hub after it has been removed from the shaft, the rear cone [2 and the threads [4 being of the same dimensions as are found on the propeller shaft, whereby the propeller shaft retaining nut may be used to secure the arbor l0 firmly in the propeller hub. The arbor may be bored out as at l 6 to lighten it. Different sized arbors may be provided for hubs of different sizes, or sleeves of appropriate contour may be provided for bushing up a smaller arbor for use in a larger hub.

The rear end of the arbor I0 carries a tool guide in the form of an extension l8, the axis of which must be coincident with the axis of the arbor since the concentricity of the reworked rings will depend on the concentricity of the extension with the arbor Ill. The extreme rear end of the extension I8 is further reduced in diameter at 20, and provided with a flanged bushing 22 which may preferably be pressed on or at least closely fitted to the reduced part 20, wherebearing for a planetary gear carrier 24. q

The carrier 24 is centrally bored for a running fit on the outside of the journal bushing 22, a

washer 26 being held to the end of the reduced" part 20 by screws 28, which precludes the bracket 24 from moving axially on the bushing 22 upon which it rotates. Two additional openings are provided near the outer ends of the arms of the bracket for the bearing bushings 3B. The axes of these two additional openings should be exactly parallel with the hub axis and may preferably be equidistant therefrom. The bearing bushings 30 may preferably be press fitted to their respective openings.

Freely rotatable in each bearing bushing 30 is a flanged feed sleeve 32, an integral externally threaded portion 34 extending rearward from each feed sleeve to receive an internally threaded gear 38 and a lock nut 38, whereby the sleeve 32, gear 36 and lock nut 38 rotate as a unit.

The assembly of the parts designated by numerals 32, 3B, 36 and 33 may be referred to as the planetary gear and hub assembly. It should be understood, however, that a journal which will rotate in the carrier 24 may be made integral with the'gear, and internally threaded by its external surface may serve as a journal pinned at 44 to prevent both rotation and axial" Pinion 40" movement in the reduced part 20; is in toothed engagement with both gears 36. A

cutter arm 46 is bored tapered to contain an: externally tapered split bushing 48. which is.v

drawn into the tapered bore by a nut 50; the nut 50 being provided with a handle 52: By cares fully maintaining the bushing, in.close .adjuste ment, the arm 46 may have the necessary rotative and axial movement on the tool guide I8: Without having noticeable play. Obviously, the bushing 48 may be omitted andithea cutter arm-- 48 fitted directly to the tool guide l8-in cases where less precision is demanded.

Externally threaded; feed screws: 54; with: axes coincident with the axes of the feed:sleeves;34;. have: an unt ireadedi portion" 56. anchored i in: the cutter arm 46- andpinnedrthereinzas atSihtcrpreclude both radial and axialcmovementr thereinz. The; external threads: ofthe feed screws: 54: are fitted: to; corresponding; internal threads in. thefeed'sleeves34. A covenfill is SBCUI'EdTtOTthEBHdSQ ofthe feed: sleeves 5.4: by screws 62;. Coven-6n: is, provided to keep: chips: or other ioreigm matter: fromrthesgearing.

The outer ends: of the cutter armz'4fi' are'boreds for: the cutterbar; 64: and: the hand crank 66, whichzare of: exactly equal diameters. The axes of; the; cuttenbar 64 and-the handrcranlc 66. are. both: parallel? to-the: aXiSTOf'thGJ-I arbor; Ill; but. the axis offihehand? cranks 66 isspacect apartfa-m ther from the arbor axis than the: axis: ofthe cutter; bar; Slip. rings of; larger diameter'may therefore be turned by. placingrthecutter-harm: theehand: crank opening; and vice versa.

Setscrews; 68 and? T: hold. the cutterbarr 64: and hand crank, 66. in. position. The: cutter bar 64 is provided with a groove 12; for the pointed; set screw 68. The-cutting bit "riszpreferabiyzot squate 512661;,13118'; bit being slifdable in: a: corresponding square opening: extending transversely. through the: end'ofthe=-cutting bar; Anzadjusting. screw- Iii which regulates the: deptir ofqtheicut to be taken-,. and azlockingzscrevir. T8rhoids; thezbitrin theadjustedposition.

The assembly of the cutter-arm 4fiiandits asso:-: ciated, parts corresponds to thecarriage of: at lathe-in that 1 it follows a1 guidewayalong; theaaxisof. relativemotation: between. the; took. and. the-.- work,. and; may therefore hereinaftei: b.8550; desi'g-e nated.

The operation; of, the; deviceds: as, follows:

The: propeller-is firstr removed. from theypro peller, shaft: and placed in, any-convenient. posttion. with, the back of the propellertowazrd therepairman. The arbor I B. is inserted in the:-pro.-- peller hub and secured with:the-.-propeller:-shaftf retaining nut,. (notshown). The screw GBLmay now. beloosened :and. the; cutter bar; 64. adjusted: axially until. the bit: 14 is. adjacent; one. of. the rings- Therscrew. 6181s then-tightened. Thebit 14. may, next. be. adj usted, torthe. desired .depth, of

cut by means. of. theadjusting. screw 16; and.

locked .withthe screw.l8. As the cutterarmAHs rotated..aboiit. the, extension. l8: by, meanszof. the crank 66;.thegears 36-.will roll-.aroundthe pinion, 40, the. gears thereby being rotatedwn, their own: axesaboutnne turn to seven turns of the crank- Hy, providing the feed, screws. 54 with: forty threads per inch, each turn of the crank advances the bit axially /7X /4o= /2a0 or about .036 in. When a rough out has been taken in this manner, the locking screw 18 may be loosened, the bit 14 removed and turned one-half turn and replaced, the screw 16 adjusted for a finished; out and locked with the screw 18. The crank 66 -is-nowturned backward which feeds the cutter arm 46 in the direction opposite of that taken for the rough cut.

Having described an embodiment of my invention, I claim:

I. A- portable turning tool for refinishing the slip rings on the rear end of an electric variable pitch aircraft propeller hub which comprises, an arbor-"adapted to fit the bore of the propeller hub, a cylindrical tool guide integral with the arbor, coaxial therewith, and extending rearwardly therefrom, therear end of said tool guide being stepped down to a smaller diameter, a flanged journal bushing carried on the said' smaller diameter, a sun: gear fixed to the rear end of. said smaller diameter, a planetary gear carrier rotat able on said journal bushing, axiallyparallel and axially equidistant internally threaded feed sleeves having rotative, bearing in said carrier, planetary gears fixed to said feed sleeve for coin cident rotation therewith and in constant meshwith;saidpinion, an adjustable bearing bushing on' saidtoolguide having 'free rotative" and axial. movement thereon, a cutter arm carried on the outside of said bearing bushing, feed screws having oneend anchored in said cutter arm and'theother end threaded and fitted to the internalthreads in said feed sleeves, a cutter bar adjust able, axially inv an axially aligned openingnear one end of said cutter arm, an adjustabletool bit in one end of said cutter bar, and a hand" crank secured in an axially aligned openinggnear the other end-ofsaidcutter arm.

2. A portable turning tool forrefinishing; the slip. rings on-the rear end of anelectric variable pitchaircraft propeller hub-which comprises; an arbor adapted to fit the bore of the propeller hub; acylindrical tool guide carried onthe arbor, c-oaxialtherewith, and extending rear-.wardly therefrom, a'journal bushing carried onthe rear end-of, said cylindrical toolguide, asungear fixed to-the-rearendof said cylindrical. tool guide, a planetary gear carrier rotatable on said journal. bushing, axially parallel and axially equidistant internally threaded feed sleeves having rotative. bearing, in. said carrier, planetary gears fixed to said feed sleeve for coincident rotation therewith. andin constant mesh with. said pinion, abearing bushing on. saidtool guide having free. rotative. and axial movement thereon, a cutter arm car.- ried on the outside of said bearing bushing, feed screws having one end anchored in said cutter. arm and the other end threaded and fitted to the internal threads'in said feed sleeves, a cutter bar" adjustable axially in an axially aligned opening near one-end of said cutter arm, an adjustable tool bit in one end of said cutter bar, and a-hand crank secured" in an axially aligned opening'near the other-end'of-said cutter-arm.

3. A portable turning tool for refinishing the liprings on an electric propeller hub'whiclicomprises, an arbor adapted to fit the bore of the propeller hub; a tool guide carried: by the-arbouand extending axially therefrom, a journali can-- riedibythe: said tool guide, a' sun gear: fixed to the rear end of said'tool guide, a'planetary gear? carrier rotatable on;said journal, axially paralleli andaxia lly equidistant internally threadediplanry gear and hub assemblies, said hubs having rotative bearing in openings in said carrier and said gears being in toothed engagement with said pinion, a cutter arm slidable axially on said tool guide, feed screws having one end anchored in said cutter arm and the other end threaded and fitted to the internal threads in said Planetary gear and hub assemblies, a cutter bar adjustable axially in an axially aligned opening near one end of said cutter arm, an adjustable tool bit in one end of said cutter bar, and a hand crank secured in an axially aligned opening near the other end of said cutter arm.

4. The device defined in claim 3 wherein the openings near the ends of the cutter arm, which are provided for the cutter bar and the hand crank, are of equal size but at different distances from the axis of the arbor.

5. A portable turning tool for refinishing the slip rings on a propeller hub which comprises.

an arbor adapted to fit the bore of the propeller 2o hub, a tool guide carried by the arbor and axially aligned therewith, a journal, coaxially supported by said arbor, a sun gear coaxially supported by said arbor, a planetary gear carrier rotatable on said journal, axially parallel and axially equidistant internally threaded planetary gear and journal units, said journals having rotative bearing in openings in said carrier and said gears being in toothed engagement with said sun gear, a cutter arm movable axially on said tool guide, feed screws having one end anchored in said cutter arm and the other end threaded and fitted to the internal threads in said planetary gear and Journal units, radially adjustable cutting means supported by said cutter arm, and means to rotate said cutter arm.

LEO T. SCHULER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,133,519 Wilson Mar. 30, 1915 2,145,091 Mansfield Jan. 24, 1939 

